In a medium bowl, whisk together the flour, eggs, milk, and salt until you have a smooth batter. It should be the consistency of thick cream.

Heat butter or oil in a large non-stick pan over medium heat. Add the sliced or crumbled sausage and cook until browned and cooked through.

Pour the batter over the cooked sausage in the pan, spreading it out slightly if needed to coat the bottom evenly. If using optional mushrooms, sprinkle them over the batter now.

Cook for 4-5 minutes, or until the edges are set and the bottom is golden brown.

Carefully flip the savory pancake and cook for another 3-4 minutes on the other side until golden and cooked through.

Slide onto a plate. Garnish generously with fresh herbs and Parmesan cheese if using.